Radially expandable non-contracting surgical stent

• US 6,638,300 B1
• Filed: 12/02/1998
• Issued: 10/28/2003
• Est. Priority Date: 12/24/1996
• Status: Expired due to Term

• Current Assignee: Cook Medical Technologies, LLC (Cook Group Incorporated)
• Original Assignee: Cook Incorporated (Cook Group Incorporated)
• Inventors: Frantzen, John J.
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): STEWART, ALVIN J
• Application Number:
  US09/203,592
• Time in Patent Office: 1,791 Days
• Field of Search: 623/1.15, 623/1.16, 623/1.17, 623/1.1, 623/1.12
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

A surgical stent (10) is provided which can be radially expanded away from a central axis (2) within a body lumen, such as an artery. The stent (10) is formed from a series of struts (20) circumscribing a cylindrical contour of the stent (10). Each strut (20) has a series of bends (30) formed therein with each bend including at least one trough (32) and at least one crest (36). Gaps (40) are provided between adjacent struts (20). Each gap (40) is spanned by an axial element such as a tie bar (50). Each tie bar (50) attaches to adjacent struts (20) through troughs (32) so that when the stent (10) is radially expanded, the struts (20) are not drawn together, but rather maintain their position and the stent (10) hence maintains its axial length without contracting. Other elements can alternatively be provided between adjacent circumferential elements to provide varying degrees of flexibility between adjacent struts (20).

Claims

1. A radially expandable axially substantially non-contracting stent for surgical implantation into a body lumen, such as an artery, said stent having a generally cylindrical contour both before and after expansion thereof, said stent comprising in combination:

at least three circumferential elements, each circumferential element forming an elongate circuit completely circumscribing said cylindrical contour, a first one of said circumferential elements defining a first end of said stent, a second one of said circumferential elements defining a second end of said stent;

each said circumferential element having a wave-like series of bends therein as each said circumferential element circumscribes said cylindrical contour of said stent;

each said bend including a trough and a crest, said trough defining a portion of said circumferential element where said circumferential element is more distant from adjacent said circumferential elements than other portions of said circumferential element, said crest defining a portion of said circumferential element where said circumferential element is closer to adjacent circumferential elements than other portions of said circumferential element;

at least one axial element having two extremities and located between at least one pair of adjacent circumferential elements, said extremities each attached to a different one of said pair of adjacent circumferential elements, joining said pair of circumferential elements together;

each said extremity attached to an adjacent one of said circumferential elements at one of said troughs;

each said circumferential element having said troughs and said crests out of phase with said troughs and said crests of said adjacent circumferential elements; and

each said circumferential element being formed from a series of attached linear segments when the stent is unexpanded, including linear trough segments oriented perpendicular to a central axis of said cylindrical contour of said stent, crest segments oriented perpendicular to said central axis and spaced axially from said trough segments by an amplitude of said circumferential elements, and inflection segments non-parallel with said trough segments and said crest segments and linking each trough segment to adjacent said crest segments.

2. The stent of claim 1 wherein said axial elements are of linear elongate form between said extremities and oriented substantially parallel to a central axis of said cylindrical contour of said stent.

3. The stent of claim 2 wherein said circumferential elements have an amplitude defined by an axial distance between one of said troughs and one of said crests, wherein each said circumferential element is spaced from adjacent said circumferential elements by a gap, said gap having a minimum width where said crests of said adjacent circumferential elements are closest to each other and a maximum width where troughs of said adjacent circumferential elements are closest to each other, each said axial element having a length equal to a sum of said amplitude and said minimum width.

4. The stent of claim 1 wherein every trough in every said circumferential element which faces an adjacent circumferential element includes an axial element located therein and attached thereto.

5. The stent of claim 1 wherein each said crest is axially spaced a similar distance from each said trough such that each said circumferential element has a constant amplitude.

6. The stent of claim 5 wherein each said trough and each said crest are bulbous at least when said stent has not yet been radially expanded, such that lateral slots in said gap between adjacent said crests of one said circumferential element are on one side of said gap and adjacent said troughs of two said circumferential elements on opposite sides of said gap are provided with a width which first decreases and then increases as said lateral slot extends away from a center of said gap and toward said circumferential element.

7. The stent of claim 1 wherein said first one of said circumferential elements defining said first end of said stent and said second one of said circumferential elements defining said second end of said stent are each formed completely of a material having means to be more opaque when viewed by an imaging device than materials forming other portions of said stent, whereby ends of said stent will more clearly appear when said stent is viewed with the imaging device.

8. A surgical stent for implantation into a body lumen, said stent having a substantially cylindrical contour and being radially expandable, the stent comprising in combination:

a plurality of circumferential elements, each circumferential element encircling said cylindrical contour of said stent;

at least two of said plurality of circumferential elements having a continuously curving undulating form extending along a length of the stent when the stent is unexpanded, including at least one trough and at least one crest as said undulating circumferential elements circumscribe said cylindrical contour of said stent;

at least one axial element located between two adjacent said circumferential elements and attached to one of said adjacent circumferential elements at a first junction and to the other of said circumferential elements at a second junction;

wherein said first junction is located spaced from said crests and said second junction is located spaced from said crests; and

each said undulating circumferential element having its at least one trough out of phase with said at least one trough of said adjacent undulating circumferential element.

9. The surgical stent of claim 8 wherein said plurality of circumferential elements includes at least three circumferential elements including a first end undulating circumferential element located at a first end of said cylindrical contour of said stent, a second end undulating circumferential element located at a second end of said cylindrical contour of said stent, and at least one intermediate circumferential element;

and wherein said stent also includes at least two axial elements including at least one first end axial element and at least one second end axial element, said first end axial element attached to one of said troughs in said first end undulating circumferential element and said second end axial element attached to one of said troughs in said second end undulating circumferential element.

10. The surgical stent of claim 9 wherein each said circumferential element includes said undulating form.

11. The surgical stent of claim 10 wherein each said circumferential element has at least one of said axial elements attached through said first junction to a trough therein and attached through said second junction to a trough of an adjacent said circumferential element.

12. The surgical stent of claim 11 wherein each said intermediate circumferential element has a first side facing said first end undulating circumferential element and a second side facing said second undulating circumferential element, both said first side and said second side having at least one trough with one of said axial elements attached thereto, said axial element attached thereto also attached to a trough of at least one adjacent said circumferential element.

13. The surgical stent of claim 11 wherein each said intermediate circumferential element has a first side facing said first end undulating circumferential element and a second side facing said second end undulating circumferential element, one said side having at least one trough with one of said axial elements attached thereto, said axial element attached thereto also attached to a trough of at least one adjacent said circumferential element, and one said side having at least one crest with a linking element attached thereto, said linking element also attached to an adjacent said circumferential element.

14. A surgical stent featuring non-contracting ends, said stent having a cylindrical contour and being radially expandable within a lumen, the stent comprising in combination:

a first end circumferential element encircling said cylindrical contour of said stent;

a second end circumferential element encircling said cylindrical contour of said stent;

at least one intermediate circumferential element encircling said cylindrical contour of said stent;

said first end circumferential element and said second end circumferential element having an undulating form including at least one trough and at least one crest as said circumferential elements circumscribe said cylindrical contour of said stent;

at least one first end axial element located between said first end circumferential element and one of said intermediate circumferential elements adjacent said first end circumferential element, said first end axial element connected to one of said troughs in said first end circumferential element and to said adjacent intermediate circumferential element; and

at least one second end axial element located between said second end circumferential element and one of said intermediate circumferential elements adjacent said second end circumferential element, said second end axial element connected to one of said troughs in said second end circumferential element and to said adjacent intermediate circumferential element.

15. A surgical stent having a cylindrical contour and being radially expandable within a body lumen, the stent comprising:

at least two pairs of circumferential elements, each circumferential element forming an elongate circuit completely circumscribing said cylindrical contour;

each said circumferential element having a continuously curving undulating form extending along a length of the stent when the stent is unexpanded and formed from a series of connected linear segments and including alternating troughs and crests as said circumferential element circumscribes said cylindrical contour of said stent;

the undulating forms of the circumferential elements of each said pair being out of phase relative to one another;

a plurality of axial elements connecting the circumferential elements of each said pair, each axial element being attached to opposing troughs of the circumferential elements of each said pair; and

at least one linking element connecting adjacent pairs of circumferential elements, said linking element extending between a crest of a circumferential element in one pair and a crest of a circumferential element in the other pair.

16. The stent of claim 15 wherein said axial elements are of linear elongate form and oriented substantially parallel to a central axis of said cylindrical contour of said stent.

17. The stent of claim 15 wherein every trough in one circumferential element of each said pair is connected to an opposing trough in the other circumferential element of said pair by an axial element.

18. The stent of claim 17 wherein every crest of a circumferential element in one pair is connected by a linking element to a crest of a circumferential element in the other pair.